Heat exchanger



w. F. HAGEN 2,503,667

HEAT EXCHANGER April 11, 1950 Filed Dec. 29, 1948 INVENTOR l /f/h'am F'- 9 BY 1 W 7% ATTORNEY.

Patented Apr. 11, 19 50v UNITED STATES PATENT OFFICE fnes'r nxcmmana William F. wellesle'y, Mam, asslgnor to Westinghouse Electric Corporation, .East Pittsburgh, Pa a corporation oi Pennsylvania Appli'c'ationbecember 29, ms. Serial No. 67,879

3Claims- This invention relates to those types 'of heat exchange units which include centrifugal fans pair of centrifugal fans having a common driving shaft, and containing an extended surface heater extending lengthwise of'the unit. The casing of such a unit has an air inlet opening in one side and an air outlet opening in another side with the heater mounted between the air inlet opening and the fans. The fans which have been 'used in such a unit in the past have had the usual scroll shaped casings around the fan wheels, and which have extended across substantial portions of the air passage between the heater and the fan inlets, and which have prevented the air passing over the heater from contacting intermediate surfaces thereof. Another disadvantage of such a unit is the cost of the two fan casings.

This invention overcomes the disadvantages described in the foregoing by omitting the scroll shaped casings around the fan wheels, and by using instead, a metal sheet having circular openings from which the walls forming the inlet passages of .the fan wheels extend; which has its longitudinal center adjacent the heater at a point adjacent its longitudinal center, and which :has portions extending from that point along diverging lines to the inlet passages of the fans. The sheet also has portions contacting the side walls of the casing and contacting the wall containing the outlet opening around the outlet opening. The sheet performs the combined functions of so guiding the air into the fan inlets that all of the surfaces of the heater are contacted by the air entering the fans, and of forming an outlet passage connecting the fan wheels with the air outlet of the unit.

An object of the invention is to reduce the cost of heat exchange units containing centrifugal fans. I

Another object of the invention is to improve the performance of a heat exchanger in a heat exchange unit.

Another object of the invention is to pass theair drawn by a pair of centrifugal fans in a heat exchange unit, in contact with all of the surfaces of the heat exchanger in the unit.

'The invention will now be described with reference to the drawing, of which; r

Fig. l is a view, "in cross section, of an air heating unit embodying this invention;

comprising the two tubes I3 with the extended surface fins l4 thereon, and .having the end headers It, extends longitudinally of the unit above the inlet grilll I and parallel thereto. The

\ pipes l6 supply steam into, and. return condensate from, the headers.

The fan wheels I 8 which preferably are of the type disclosed in the H. F. Hagen Patent No. 2,117,416, are mounted on the shaft l9 which extends longitudinally within the unit above the heater, and have their inlets 29 facing the opposite end walls '20 of the unit. The shaft is supported in the bearings 2| attached to the end walls 20, and has on one end, external the casing, the pulley 22. The electric motor 23 is supported on the top of the unit, and has a shaft with the pulley 24 thereon, and which rotates through the belt 25 and the pulley 22, the shaft 19 and the fan wheels ll.

The 'air guiding metal sheet 28, a perspective view of which is shown by Fig. 3, has the circular openings 2'! adjacent its ends and has its walls 39 around the openings formed, as by spinning, to provide the curved walls of the inlet passages 30 for the fan wheels 18.

For installation in the unit, as illustrated by Figs. 1 and 2, the sheet is bent at its longitudinal center along a transverse line to form the apex it which may be spaced about ten inches above the upper surface of the heater. The portions of the sheet between the apex and the passages ill extend from the apex along diverging lines. The upper edges of the sheet contact the upper wall of the unit at the edges of the air outlet grill walls of the unit, limits the air entering the fan wheels to that passing over theheater. The sheet, together with the side walls of' the unit,

form an enclosure around the fan wheels. cans.-

ing all of the air delivered thereby to be discharged through the outlet grille l2.

The sheet 28 is preferably formed from a single metal sheet with the walls for the fan inlet P sages 30 formed by spinning. The sheet is easily bent in a single operation to form the apex 3i, and is easily installed in the unit. The construction not only is relatively inexpensive but its use results in a unit having an improved performance over that of the prior units which used centrifugal fans having scroll shaped casings.

While one embodiment of the invention has been described for the purpose of illustration, it should be understood that the invention is not limited to the exact apparatus and arrangement of apparatus illustrated, as modifications thereof may be suggested by those skilled in the art, without departure from the essence of the invention.

What is claimed is:

1. A heat exchange unit comprising a rectangular casing having an air inlet opening in one wall and an air outlet opening in another wall, a heat exchanger within the casing adjacent the inlet opening, a rotary fan shaft within the casing between the heat exchanger and the outlet opening, a pair of fan wheels on said shaft, said wheels having oppositely disposed inlets, and means forming a partition having inwardly turned portions forming inlet passages into said inlets of said wheels, having other portions extending from adjacent said heater along diverging lines to said inwardly turned portions, and having other portions contacting said one wall on opposite sides of said outlet opening,

2. A heat exchange unit comprising a rectangular casing having an air inlet opening in one wall and an air outlet opening in another wall, a heat exchanger within the casing adjacent the inlet opening, a rotary fan shaft within the casing between the heat exchanger and the outlet opena Number ing, a pair of fan wheels on said shaft, said wheels having oppositely disposed inlets, and a. metal sheet having inwardly turned portions forming inlet passages into said inlets of said wheels, and having other portions extending from its center along diverging lines to said inwardly turned portions, and having other portions contacting said one wall on opposite sides of said inlet opening.

3. A heat exchange unit comprising a relatively long and relatively narrow, rectangular casing having an air inlet opening in one wall and having an air outlet opening in another wall, a longitudinally extending heat exchanger within said casing, said exchanger extending parallel to said inlet opening, a rotary fan shaft extending between the end walls of said casing parallel to said heat exchanger, a pair of fan wheels on said shaft, said wheels having oppositely disposed inlets, and a metal sheet having inwardly turned portions forming inlet passages into said wheels, having other portions extending from its center along diverging lines to said inwardly turned portions, having other portions contacting said one wall on opposite sides of said outlet opening, and having other portions contacting side walls of said casing.

WILLIAM F. HAGEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Seelert Oct. 21, 1930 Young May 12, 1936 

